The invention relates to an ear wax guard for a hearing aid which comprises at least a microphone, an amplifier unit and a receiver, in which sound signals picked up by the microphone are amplified in the amplifier unit, are converted into acoustic signals by the receiver, and are delivered via a sound channel to the eardrum, and in which the ear wax guard can be fitted entirely or partially into the sound channel.
International Patent Publication WO99/07182 A2 discloses an acoustic coupler with an ear wax guard. On assembly of the coupler, a receiver is mounted in a housing which is provided with a thread or a toothed surface and in this way can be screwed into the coupler or can be locked in notches of the coupler.
International Patent Publication WO 00/03561 discloses an ear wax guard which can be inserted into the sound outlet opening of a hearing aid and can be removed from this again for replacement. The ear wax guard has a substantially cylindrical outer shape and is provided with a bead via which the ear wax guard is secured in a sound tube. A disadvantage of this securing method is the non-uniform force which is exerted on the sound tube upon insertion of the ear wax guard into the sound tube and upon its removal therefrom. In the least favorable scenario, this can lead to the sound tube coming loose from the housing of the hearing aid in the area of the sound outlet opening. Moreover, the bead can lead to a kind of memory effect in the sound tube. In this way, there is a permanent deformation of the sound tube in the area of the bead. However, this impairs the securing of the ear wax guard in the sound tube and can even lead to its loss.
U.S. Pat. Nos. 5,864,628 and 5,712,918 disclose ear wax guards which, in the area of the sound outlet opening of a hearing aid, can be inserted into and removed from a sound tube. The front end of the known ear wax guard narrows in a frustoconical shape, which makes it easier to insert the ear wax guard into the sound tube. Moreover, the front end has a greater diameter than the remaining part of the ear wax guard to be inserted into the sound tube. In this way too, as in the above-mentioned publication WO 00/03561, a kind of bead is formed which engages in the sound tube and secures the ear wax guard in the sound tube. Therefore, the disadvantages mentioned for publication WO 00/03561 also arise in this case.